Solution:
Use the Cargo Hold Fix mod to make cargo vehicles (trains, trucks, ships, planes) wait longer to fill up more.
Phoenix C64 says:
"I know this mod is more about traffic related to roads... but I know it also affects trains to some degree as I had to turn off TMPE at one point because it was affecting my trains in some bad way. (spend 3h. trouble shooting the problem and disabling TMPE fixed the issue)
Now, I currently have a big complaint about trains: trains only take 1-2 cargo trucks as a load and bottleneck my train network with 7-13% filled trains.
Could TMPE have an option so trains don't spawn until they have an X% of load (let's say 50%)"
VictorPhilipp/Cities-Skylines-Traffic-Manager-President-Edition#136
Phoenix C64 says:
"I know this mod is more about traffic related to roads... but I know it also affects trains to some degree as I had to turn off TMPE at one point because it was affecting my trains in some bad way. (spend 3h. trouble shooting the problem and disabling TMPE fixed the issue)
Now, I currently have a big complaint about trains: trains only take 1-2 cargo trucks as a load and bottleneck my train network with 7-13% filled trains.
Could TMPE have an option so trains don't spawn until they have an X% of load (let's say 50%)"
VictorPhilipp/Cities-Skylines-Traffic-Manager-President-Edition#136